1. Field of the Invention
The present invention relates to an apparatus and method for diagnosis and therapy of skin diseases and, more particularly, to an apparatus and method for photodynamic diagnosis and therapy of skin diseases and a light source system thereof that can improve the efficiency of skin diagnosis by accurately analyzing skin conditions using fluorescence and white light simultaneously and further carry out fluorescent diagnosis and photodynamic therapy in the same skin region simultaneously.
2. Background Art
Recently, a variety of skin diagnosis apparatuses can be found in cosmetic shops, skin care clinics, and the like. With the skin diagnosis apparatus, a user can analyze and diagnose its skin condition so as to select cosmetics suitable for the skin condition or to find a problem in its skin condition and obtain a solution to the problem.
Among them, a skin diagnosis apparatus using a diagnostic lamp has been widely used for diagnosing the skin condition by irradiating a light beam of a predetermined wavelength onto the skin and analyzing a specific fluorescence emitted from the skin.
Conventional skin diagnosis apparatuses will be described with reference to literatures as follows.
Skin pores of a human body have sebaceous glands producing sebum.
The sebaceous glands in a healthy body secrete an appropriate amount of sebum from the skin pores to the skin surface to form a sebaceous membrane acting as a natural protecting layer.
However, an unhealthy body secretes an excessive amount of sebum and the sebum excessively secreted soon becomes oxidized by air.
Then, the oxidized sebum becomes stickier and clogs the pores.
Bacteria propagate in the thus clogged pores and porphyrins are produced from the bacteria.
The produced porphyrin emits light in response to ultraviolet light.
Accordingly, a skin diagnosis apparatus using porphyrin properties responsive to ultraviolet light has been developed.
The conventional skin diagnosis apparatus uses a method in which an ultraviolet lamp irradiates a patient's entire face in a dark box to observe a change in fluorescence intensities with naked eyes through a detector.
Meanwhile, optical fiber light sources based on the use of various kinds of lamp, such as halogen, xenon, metal-halide, mercury, etc., which are well known for the purpose of photodynamic diagnosis and therapy of diseases are developed and widely used.
Such lamps have been selected to meet the apparatus requirements in terms of specific medical purposes and means, technical and economical aspects.
In a case where a complicated operation that should use a wide range of light intensities or a variety of light beams of selective wavelengths is required, the use of a single lamp could not provide an optimal method in general.
In this case, the developer of the apparatus has depended on a lamp having a specific function or used a plurality of lamps simultaneously to overcome the drawbacks.
Especially, it has been known that it is necessary to observe geometry, position, color of an examination region by a white light in addition to the observation of fluorescence generated from the examination region by an excitation light irradiation in diagnosing diseases using fluorescence.
Advantages, possibilities and recent trends in use of fluorescence diagnosis (FD) and photodynamic therapy (PDT) of skin diseases using a photosensitizer including 5-aminolevulinic acid (5-ALA) have been described in the reference literature (C. Fritch and T. Ruzichka, “Fluorescence Diagnosis and Photodynamic Therapy of Skin Diseases”, Atlas and Handbook, 2003, Springer-Verlag. Wien).
According to the literature, a fluorescence image of a dermal layer is recorded in the form of a photograph in such a manner that the examination region is exposed to ultraviolet light of a Wood's lamp in a dark room for 0.25 to 1.5 seconds to take a photograph and the photograph is developed with a high speed film such as 1600 ASA.
Meanwhile, U.S. Pat. No. 5,363,854 has disclosed a method for detecting anomalies of the skin, more particularly melanoma, and an apparatus for carrying out the method, in which an ordinary video camera fixed with a light source in a picture processing unit is used for detecting a fluorescence picture of an examination region and a reference picture.
The apparatus includes a light source for illuminating a two-dimensionally extending examination region of the skin, successively, with ultraviolet light range and with visible light.
The camera records a fluorescence picture of the examination region having signal values F(x,y) at its picture points x,y in response to the illumination with ultraviolet light and a reference picture having signal values R(x,y) at its picture points x,y in response to the illumination with visible light.
A memory stores the signal values of at least one of the fluorescence picture and said reference picture, and a processor responsive to the memory produces an output picture having respective signal values A(x,y) at its picture points x,y which are formed from respective quotients F(x,y)/R(x,y) of the signal values of the fluorescence and reference pictures at the same picture points.
The image observed through an ocular of the apparatus is reorganized with two color images through a dichroic mirror.
The light source operates under continuous conditions or under impulse conditions and it saves energy and reduces the effect of extraneous light under the impulse conditions.
The apparatus for detecting skin diseases includes an excitation light source for generating fluorescence from the examination region.
The fluorescence generated along the reference light are divided by a beam splitter and sent to respective optical paths, the respective optical paths produce images in the examination region, and an optical coupler provides the images produced by the respective optical paths so that a user can observe the images with naked eyes.
U.S. Pat. No. 5,760,407 has proposed a device for the identification of acne, microcomedones, and bacteria on human skin.
Meanwhile, for the purpose of the diagnosis of skin diseases, there have been developed a series of photo-diagnostic methods using spectroscopy and imaging methods.
For the purpose of the skin therapy, there have been disclosed phototherapy methods by the action of electromagnetic radiation, and fluorescence diagnosis and photodynamic therapy (PDT) occupy an important place in such a series of photo-diagnostic methods.
In case of the fluorescence diagnosis, fluorescent characteristics observed in the diseased tissue region and in the normal tissue region are different from each other, and this difference is shown as emitted wavelength and fluorescence intensity.
One of the drawbacks in the spectroscopic wavelength calibration is that the spatial resolution in the examination region is low and the number of spots examined is small.
The method of obtaining the fluorescence image from the examination region eliminates the above drawback and the fluorescence images observed in most cases are given in the form of a monochrome fluorescence image.
Accordingly, for the purpose of an accurate morphological analysis, a color image acquired simultaneously by a white light from the same examination region is supplemented with the monochrome fluorescence image [simultaneous acquisition and display of morphological (color image) and physiological (fluorescence image) information) (DYADERM professional, Biocam GmbH; http://www.biocam.de].
However, as the monochrome fluorescence image loses information showing the difference of wavelengths in the individual skin regions, the quality of the image is substantially poor and it makes it difficult to investigate the cause of the fluorescence in study on the intrinsic fluorescence characteristics produced in the skin itself.
Meanwhile, it is possible to combine the advantages of the fluorescence spectroscopy method and the fluorescence imaging method by a multispectral imaging system [Hewett et al., 2000, “Fluorescence detection of superficial skin cancer,” J. Mod. Opt. 47, 2021-2027].
Moreover, the basic spectroscopic information of the fluorescence produced from the skin can be obtained from the visible light region and thereby it is possible to apply a high sensitive color camera to the multispectral imaging system, thus simplifying the configuration of the apparatus and improving the spatial resolution as well.
A facial image of color fluorescence can be taken using the Clarity Pro facial image scanner manufactured by Moritex USA Inc. [http://www.moritexusa.com] and this scanner provides a fluorescence image using an ultraviolet light illumination and mainly concentrates on the examination of the facial skin.
However, UV-Scope of Moritex USA Inc. can examine other regions of the body as well as the face. The configuration of such an apparatus has been disclosed in European Patent No. EP1488737, Chinese Patent No. CN1572250 and U.S. Patent Publication No. 2004-0257439 A1, and shown in FIG. 1 of the present application.
According to the skin observing apparatus capable of observing the skin tissue, it is possible to observe blotches caused from subcutaneous pigmentation and skin roughness caused from keratin abrasion by a single unit of an image pick-up device without using polarization.
The apparatus includes an image pick-up head 3 having a view hole 2 to be in contact with a skin, provided inside the image pick-up device, an image pick-up device 4 for picking-up an image of the skin through the view hole 2, and an illumination system comprising three systems 5A, 5B and 5C.
That is, the illumination system comprises a tissue observing illumination system 5A for irradiating a white light to the view hole 2 along an image pick-up light axis X, a keratin abrasion observing illumination system 5B for irradiating a white light to the view hole 2 from the lateral direction thereof, and a subcutaneous pigment observing illumination system 5C for irradiating a UV-light to the view hole 2.
However, the above apparatus has some drawbacks in that it may be harmful to the skin since it observes the fluorescence (UV imaging mode) only by the UV excitation means and it may reduce the possibility of the fluorescence diagnosis since the depth of the skin diagnosis is low.
Moreover, it is efficient that a blue light having a main peak at a wavelength of 400 nm be used rather than the ultraviolet light for the purpose of the diagnosis of acne disease, skin cancer, etc., since the photosensitizers (photo-accelerators or contrast agents) including 5-ALA and the porphyrins in Propionibacterium acnes have a main absorption band in the vicinity of a wavelength of 400 nm.
The above apparatus has a further drawback in that it cannot carry out the photodynamic therapy (PDT).
In addition, the apparatus has a drawback in that, if the UV LED lights are arranged circularly around the image pick-up light axis X and the illumination light axes XC are collected to the center of the view hole 2, the illuminated regions by the LED lights should overlap each other based on the light axis X in order to obtain a UV illumination light of a uniform intensity in the view hole 2, and thereby the illuminated regions by the LED lights are limited to a very narrow range.
A specific light source is used for the purpose of the photodynamic therapy. The light source for the photodynamic therapy used in the skin care field may be coherent or non-incoherent. The non-coherent light source is generally cheaper than the coherent one and can be used together with other photosensitizers as it allows the illumination in a wider wavelength range.
One of the non-coherent light sources widely used for carrying out the photodynamic therapy is Model LC-122M manufactured by LumaCare [http://www.lumacare.com/genprod.htm; Non-Coherent Light Sources for PDT].
As the light source in such a light source system, a halogen lamp having a wavelength range of 400 nm to 800 nm and an output power of 20 mW/cm2 to 1000 mW/cm2 is mainly used and the light is transmitted through replaceable optical guides to the necessary region of the patient's skin.
However, the above apparatus has no function of taking a fluorescence image like the other non-coherent light sources having optical fibers for carrying out the PDT.
As described above, the apparatus for providing the fluorescence image and the apparatus for the photodynamic therapy using the non-coherent light source having light guides for the light transmission are separately manufactured in accordance with the intended use.
That is, such apparatuses are manufactured separately for the fluorescence diagnosis and not for the photodynamic therapy or, on the contrary, for the photodynamic therapy and not for the fluorescence diagnosis.